In this book which is the first of the "Myth" series of books by Robert Asprin, we are introduced to Skeeve who is a budding thief learning magic from Garlak on the world of Klah. Skeeve's life is turned upside down when Garlak is assassinated and Skeeve is left facing a demon. As it happens, the Demon is not your typical demon and actually is Garlak's friend from another dimension. Aahz is from the dimension of Perv and is a master magician himself...except Garlak, as a practical joke, has caused Aahz to lose all his powers and since Garlak is dead, he can't restore them nor can he return home. Aahz agrees to continue Skeeve's training while investigating Garlak's murder. From here, a friendship is built which will continue for several more books.
This series of books is tongue-in-cheek and if you can't take puns, this series is not for you.
This report prepared by Preston